Reports the day of the M7.3 earthquake

2025 Magnitude 7.3 Sand Point Earthquake
Alaska Earthquake Center article posted the evening of July 16.

The Earthquake Center's Michael West, the state seismologist, gives an update on
the magnitude 7.3 earthquake several hours after the earthquake happened.

Shaking duration

We had a number of people ask how long the shaking lasted. Below is a map created by one of our graduate student researchers, showing how the Alaska Earthquake Center's 5 closest seismic stations recorded the ground motion. Each triangle shows a station, and the box closest to it is the recorded shaking, in %gravity. Shaking is typically reported as MMI (modified Mercalli intensity), where MMI III is weak to light shaking (~0.17% g) and MMI V is moderate to strong shaking (>3.9% g). You see each box shows the duration of shaking of light and strong levels, also marked on the seismograms. The station closest to the earthquake had 14 seconds of strong shaking, and nearly 1.5 minutes of weak shaking. Learn more in our webstory How long does shaking last?

Learn More

Listen to Episode 51: "The July 16, 2025 M7.3 Sand Point Earthquake" of our What's Shaking Alaska?! radio series.